A Sub procedure named GetEndingInventory is passed four Integer variables named intBegin, intSales, intPurchases, and intEnding. The procedure should calculate the ending inventory using the beginning inventory, sales, and purchase amounts passed to the procedure. The result should be stored in the intEnding variable. Which of the following procedure headers is correct?

a. Private Sub GetEndingInventory(ByVal intB As Integer, ByVal intS As Integer, ByVal intP As Integer, ByRef intFinal As Integer)

b. Private Sub GetEndingInventory(ByVal intB As Integer, ByVal intS As Integer, ByVal intP As Integer, ByVal intFinal As Integer)

c. Private Sub GetEndingInventory(ByRef intB As Integer, ByRef intS As Integer, ByRef intP As Integer, ByVal intFinal As Integer)

d. Private Sub GetEndingInventory(ByRef intB As Integer, ByRef intS As Integer, ByRef intP As Integer, ByRef intFinal As Integer)